/**
 * ***************************************************************************** Copyright (c) 2005,
 * 2008 IBM Corporation and others. All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: IBM Corporation - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.ltk.core.refactoring.model;

import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.resources.mapping.ModelProvider;
import org.eclipse.core.resources.mapping.ResourceMapping;
import org.eclipse.core.resources.mapping.ResourceMappingContext;
import org.eclipse.core.resources.mapping.ResourceTraversal;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.ltk.core.refactoring.RefactoringDescriptorProxy;
import org.eclipse.ltk.core.refactoring.history.RefactoringHistory;
import org.eclipse.ltk.internal.core.refactoring.RefactoringCorePlugin;
import org.eclipse.ltk.internal.core.refactoring.history.RefactoringHistoryService;

/**
 * Partial implementation of a resource mapping for a refactoring history object.
 *
 * <p>Note: this class is intended to be implemented by clients which need to enhance a model
 * provider with a refactoring model.
 *
 * @see ResourceMapping
 * @see ModelProvider
 * @since 3.2
 */
public abstract class AbstractRefactoringHistoryResourceMapping extends ResourceMapping {

  /** The refactoring history */
  private final RefactoringHistory fRefactoringHistory;

  /** The resource traversals */
  private ResourceTraversal[] fResourceTraversals = null;

  /**
   * Creates a new abstract refactoring history resource mapping.
   *
   * @param history the refactoring history
   */
  protected AbstractRefactoringHistoryResourceMapping(final RefactoringHistory history) {
    Assert.isNotNull(history);
    fRefactoringHistory = history;
  }

  /** {@inheritDoc} */
  public boolean equals(final Object object) {
    if (object instanceof AbstractRefactoringHistoryResourceMapping) {
      final AbstractRefactoringHistoryResourceMapping mapping =
          (AbstractRefactoringHistoryResourceMapping) object;
      return mapping.fRefactoringHistory.equals(fRefactoringHistory);
    }
    return false;
  }

  /** {@inheritDoc} */
  public final Object getModelObject() {
    return fRefactoringHistory;
  }

  /** {@inheritDoc} */
  public final IProject[] getProjects() {
    final Set set = new HashSet();
    final IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
    final RefactoringDescriptorProxy[] proxies = fRefactoringHistory.getDescriptors();
    for (int index = 0; index < proxies.length; index++) {
      final String name = proxies[index].getProject();
      if (name != null && !"".equals(name)) // $NON-NLS-1$
      set.add(root.getProject(name));
    }
    return (IProject[]) set.toArray(new IProject[set.size()]);
  }

  /**
   * Returns the associated resource.
   *
   * <p>This method only returns a meaningful result if the history contains refactorings of a
   * single project.
   *
   * @return the associated resource, or <code>null</code> if the refactoring history contains
   *     workspace refactoring descriptors only, or if it contains refactoring descriptors from
   *     multiple projects.
   */
  public final IResource getResource() {
    try {
      final ResourceTraversal[] traversals = getTraversals(null, null);
      if (traversals.length > 0) {
        final IResource[] resources = traversals[0].getResources();
        if (resources.length > 0) return resources[0];
      }
    } catch (CoreException exception) {
      RefactoringCorePlugin.log(exception);
    }
    return null;
  }

  /** {@inheritDoc} */
  public final ResourceTraversal[] getTraversals(
      final ResourceMappingContext context, final IProgressMonitor monitor) throws CoreException {
    if (fResourceTraversals == null) {
      final IProject[] projects = getProjects();
      final ResourceTraversal[] traversals = new ResourceTraversal[projects.length];
      for (int index = 0; index < projects.length; index++)
        traversals[index] =
            new ResourceTraversal(
                new IResource[] {
                  projects[index].getFolder(RefactoringHistoryService.NAME_HISTORY_FOLDER)
                },
                IResource.DEPTH_INFINITE,
                IResource.NONE);
      fResourceTraversals = traversals;
    }
    final ResourceTraversal[] traversals = new ResourceTraversal[fResourceTraversals.length];
    System.arraycopy(fResourceTraversals, 0, traversals, 0, fResourceTraversals.length);
    return traversals;
  }

  /** {@inheritDoc} */
  public int hashCode() {
    return fRefactoringHistory.hashCode();
  }
}
